Cervical discectomy with total disc replacement

The aim of these operations is to relieve arm pain and or numbness and weakness affecting the arms or the legs. They are generally not designed to relieve neck pain.

In both types of surgery the damaged disc is removed and the nerve decompressed. There is a choice as to how to reconstruct the spine after discectomy.

In total disc replacement the damaged disc is replaced with an artificial disc thus preserving motion. The design of these artificial discs has improved dramatically and is an immensely complex process which aims to restore the normal physiology.

In fusion the damaged disc is replaced with a bony bridge between the vertebrae. This stabilises the two bones/vertebrae. Again, the devices used to achieve fusion are complex and represent a major advance on methods available only a few years ago. They usually involve plates, cages, screws and bone graft which may be artificial or harvested from you.

Fusing a disc inevitably transfers work to the adjacent discs. So, unless there is a good reason to fuse the spine, the usual course is a disc replacement as this offers to restore and or preserve movement at the affected level.

Disc replacement is therefore now more common than fusion after disc removal though the evidence that it is actually better is not as tight as you might think. Both operations are good. Your big decision is whether to have surgery or not. If you have spent more time thinking about replacement vs fusion your mind has been focused on the wrong issue - though this is an important decision too.

Fusion is needed if there is significant instability at the operated level – spondylolisthesis or if there is a fracture as well as a prolapse.

Fusion is also used if the disc space is already very narrow when the movement has already been lost. If the facet joints are also worn and painful then disc replacement can make this worse. Finally, if there are a lot of osteophytes then these have to be drilled away. As a result of this bone work, the two vertebrae can fuse around the replacement – this happens more often with some discs than others and may occur as many as one in ten times.

Disc replacement is not a guarantee of no more trouble nor does it prevent all disease in the adjacent levels. You wore out the first disc without having had a fusion so you may also wear out another. That said, our philosophy is to preserve and restore function where possible.

Is there good evidence to prove disc replacement is better? Not in the form of randomised trials. Such trials are difficult to do, they have been flawed and to some degree inconclusive. In our view, this reflects the difficulty of doing this kind of study. For most patients, a logical choice can be made and where there is doubt we would opt for disc replacement – you can fuse after if it does not work but you cannot reverse a fusion.

The Operation: Cervical Discectomy

Once you are anaesthetised, you are placed face up on the operating table. A horizontal, gently curved incision, approximately 3 cm long, is made just to the right of the Adam’s apple usually within an existing skin crease. We use an X-ray machine (Image Intensifier) to help us locate the correct position. Local anaesthetic is used to numb the nerves in this area and so lighten the anaesthetic needed. The muscles on the side of the neck are then parted and the front of the spine identified and exposed. The correct level is then again confirmed with an X-ray. Special retractors are used to hold the soft tissues safely aside – these include the larynx (wind pipe), the oesophagus (swallowing tube), carotid artery and jugular vein. Another special distractor instrument is then used to hold the vertebral bones slightly apart so as to create space to work in. It spans the bones and discs to be operated on/removed. Everything up to this point is referred to as “access”.

Access is gained via a small incision on the front of the neck and is guided by X-Ray

The operating microscope is then brought in and the surgeon works thereafter looking through this scope – it brings superb illumination as well as magnification to allow precise operating. Now the main part of the operation begins.

Gradually, the back of the disc and any osteophytes are cleared and the central canal is exposed thus gradually relieving the pressure on the spinal cord. This surgical part of the procedure is termed central canal decompression and the operation has slowed to a snail’s pace at this point as the spinal cord is immediately below. A specifically designed high speed air drill is used to carefully drill away any compressing bone.

The nerves exiting the spine on either side are now cleared of any disc prolapse or osteophytes. This element of the operation is termed nerve root decompression. The removal of the disc prolapse itself is termed a discectomy.

A degenerate disc is seen prolapsed and compressing the exit of the right nerve root as well as distorting the spinal cord. The nerve roots are compressed on both sides more laterally by bulging disc material.

Here the red area and blue arrows indicate the area that is cleared in discectomy and nerve root decompression.

Reconstruction

Following a discectomy, there are two different methods for cervical spine reconstruction: disc replacement or a spinal fusion.

Prior to the surgery we will have discussed which is the best method of reconstruction for you. Disc replacement or fusion: which is best for me?

Once the decompresion is complete and the damaged disc has been cleared the ends of the exposed bones above and below are meticulously cleared of all fragments of disc and soft tissue so as to expose healthy bone. This is crucial if the plates of the artificial disc are to bond to the bone. Unlike in fusion reconstruction, no bone graft is needed for this operation and so no extra incisions are needed to harvest it.

Before the surgery we will also have discussed with you the range of artificial discs available and will recommend the one we feel appropriate for you. We feel the choice is crucial.

Disc Replacement

Once you have had your offending disc removed a disc replacement procedure can be performed as the cervical spine reconstruction.

Closure

After the reconstruction is complete, the wound will then be stitched in layers using internal absorbable stitches. Often the final stitch runs under the skin and has to be removed some five days later.

Informed consent

Before you have a procedure of any kind, however trivial you may feel it to be, you must be fully aware of the possible and likely consequences. You have to sign a consent form in which you state that you are fully aware. We will go over this with you in your consultation. Do not sign the consent form for a procedure with us unless you feel fully informed of its aims and risks, as well as the alternatives.

Much of this will have been discussed in our consultations. Essentially, an operation is always the last resort. Instead, you could try injections or further conservative treatment (physiotherapy, osteopathy, chiropractic, acupuncture, tablets and time). Obviously, we will usually have formed the view that these are unlikely to bring you to comfort any time soon before recommending surgery. For the majority, it is pain that drives the surgery. In these circumstances, you have to feel that the degree of pain warrants the risk and effort involved in putting yourself through the operation.

*If you feel you are developing unexpected troublesome or worrying symptoms, do not hesitate to call The Spine Surgery London or the ward staff, who will be able to guide you. Please go to Contact Us page for suitable contact numbers.

When will I next see you after my operation?

Our usual routine is to see patients three to four weeks after discharge and it is at this point that we can start the physiotherapy. Often there is a need for follow-up X-rays so it is useful to have the old ones for comparison, so please bring these with you. We usually then see you after another six weeks and then after a further three months.

When can I go back to work?

This may reasonably be anytime between four and twelve weeks post surgery.

If, once you get home problems arise, help is available from a number of sources. Firstly, if it is during working hours, you may ring The Spine Surgery London. If it is out of hours, our voicemail will tell you what to do in the event of an emergency. Secondly, you may ring the hospital and ask to speak to our Spinal Nurse Specialist. In her absence, you should ask to speak to the hospital’s Duty Manager or to the ward staff (please go to Contact Us page for more information).

You may of course contact your general practitioner or any emergency service, should you so wish or if the other avenues fail.

We do not provide a 24 hour emergency service but can respond on most occasions.

For more concise pre-operative and post-operative information regarding cervical discectomy and disc replacement, please press here for an information pack.